Solar trackers are used to rotate photovoltaic (PV) modules to keep them perpendicular to the direct rays of the sun. Keeping the PV modules, as part of an array, at this orientation increases or optimizes the amount of energy that can be generated by the array, because energy generated by the array drops off with the cosine of the angle of incidence of solar rays on the surface of the array. Although trackers add an additional cost per watt over fixed ground-mount systems, the cost is typically recouped on arrays of one megawatt or larger.
In a single-axis tracker, photovoltaic modules are suspended above the ground in one or more horizontal rows, connected to a beam referred to as a torque tube. The torque tube is generally oriented along a North-South axis, and is attached to a drive mechanism actuated by a controller to rotate the photovoltaic modules attached to the torque tube over the course of the day to maintain a substantially constant angle with the sun as the sun progresses through the sky.
More sophisticated trackers may include dual-axis trackers that not only rotate modules from East-to-West but also tilt modules in a North-South direction toward the equator. With dual-axis trackers, modules are usually clustered together in individual sections, spaced apart from one another since they need greater spacing due to intra-row shading (shading of one section by an adjacent section in the same row), in addition to the inter-row shading also present in single-axis trackers.
Because tracker arrays require very little post installation maintenance, the viability of tracker array projects often turns on the projected rate of return derived from comparing the fixed value of the energy generated over the lifetime of the system versus the upfront costs of the hardware and of the installation. In a multi-megawatt project, cost reductions of pennies per watt can be the difference between a project being viable or too expensive. Therefore, tracker designers are always seeking innovations to lower installation and hardware costs.
Accordingly, there remains a need for photovoltaic module assembly hardware that can make installation of solar tracker arrays more efficient and cost effective.